it would feel like an extra 50+ hp it would be very hard not to burn tires in first gear, in otherwords u could start off in 2 gear and it woiuld be like you got pushed of the line,, your gas mileage would go to sh**t . the cost for a 390 diff for your car would run between 5 to $700 i do no have facebook don't want it either 954 336 3405